Submerged Aerated Filter (SAF) technology was introduced by Veolia over two decades ago, and has been continually developed to include units to treat both municipal and industrial wastewater from 30 population equivalent (PE) upwards.
Overview
The BioSAF is an upflow Bioreactor which employs a high-efficiency neutral buoyancy plastic media. The BioSAF consists of a containment vessel made in either GRP, GCS, coated mild steel, stainless steel or concrete with individual dividing walls, internal air and water distribution systems, charge of plastic media and internal support structure.
The BioSAF is available in three forms:
- Integral BioSAF Package Plant (30 - 250 PE)
- Modular BioSAF (up to 800 PE, or in
- Custom-Built BioSAF (1000 PE +)
* SAF and BioSAF are registered trademarks of Veolia Water Technologies.
Main Features & Benefits
- Established / robust fixed film technology
- Resilience to shock and toxic loads
- Suitable for below-ground, partially buried or above-ground installation
- Compact footprint
- Low environmental impact
- Minimal operational input required
- Low whole-life costs, such as energy consumption
- Design provides accurate sizing and guaranteed effluent discharge quality
- Random packed media with a surface area in the range of 100 to 400 m2/m3 and a voidage of 95%
- High media voidage reduces or eliminates the requirement for backwashing
- Typical design detention times provide buffering ability to handle peak loadings characteristic of smaller works
- Containerised sizing for ease of transport to site
Typical Applications
BioSAF Intergral Package Units
- Industrial sites
- Small communities, housing estates, hotels, caravan parks
- Ideal for environmentally-sensitive areas
BioSAF Modular Units
- Roughing, secondary or tertiary applications
- Remote sites
- Can be used to provide temporary treatment during upgrade
Applications
The BioSAF is capable of attaining discharge standards of 20 BOD5 : 30 TSS : 5 NH4-N (95%-tile), offering optimised plant performance and provide increased process security.
The BioSAFTM is an upflow Bioreactor which employs a high-efficiency neutral buoyancy plastic media, ideally suited to both BOD5 removal and nitrification of wastewater.
The BioSAFTM consists of a containment vessel made in either GRP, GCS, coated mild steel, stainless steel or concrete with internal dividing walls, internal air and water distribution systems, charge of plastic media and internal support structure.
The media provides a large surface area on which the bacteria attach themselves to grow and live.
Wastewater is introduced into the base of the BioSAFTM unit into the under decking plenum space. Air is introduced into the BioSAFTM through a separate diffuser system also located near the base of the unit. An air blower supplies oxygen to the BioSAFTM environment on a continuous basis. The air and water distribution system design is such that it creates a very effective mixing pattern within the BioSAF. This pattern allows for rapid distribution of the wastewater throughout the packed media bed, which produces a homogeneous solution in full contact with the entire microbial population for the period of time that the wastewater is in the reactor.
The uniform mixing pattern is of key importance in providing a stable environment which has the ability to smooth out fluctuations that may occur in the influent concentrations. The high media voidage eliminates the need for backwashing, thus reducing the costs and ensures minimal disruption of the biological process.
Because of the high media porosity, BioSAFTM is characterised by high retention times, making them ideally suited to both BOD5 removal and nitrification of wastewater. The neutral buoyancy of the media also simplifies reactor construction and maximises active biological volume.
